This invention relates to a channel selection device used in a television receiver for receiving a digital/analog broadcast and a digital/analog broadcasting receiver equipped with the same.
There has conventionally been available such a digital/analog broadcasting receiver that is capable of selecting a channel to display a list of channel information obtained by analyzing a broadcasting signal in order to facilitate channel selecting operations (see, for example, Japanese Unexamined Patent Publication No. 55-26760). There is also available such a receiver that automatically switches to such a channel that is capable of higher quality reception if the reception quality deteriorated (see, for example, Japanese Unexamined Patent Publication No. 2000-165766).
By the ATSC (Advanced Television Systems Committee) Standard of the North America Digital Broadcasting, besides a prior art analog broadcast, there are originated a BS (Broadcasting Satellite) digital broadcast capable of high-picture-quality and multi-channel broadcasting and a digital broadcast represented by the CS (Communications Satellite) digital broadcast, each of which digital broadcasts is originated in a carrier wave in a predetermined frequency band through a physical channel different from that for analog broadcasting, thus generally containing many contents. Other digital broadcasts originated from the same broadcasting station or the same system of broadcasting station as the prior art analog broadcasting station are managed so that the station can be selected and displayed through a virtual channel assigned the same channel numbers as the prior art analog broadcasting channel numbers in order to facilitate the operations of the users accustomed to these prior art channel numbers.
The digital broadcasting virtual channels comprise one main channel and sub-channels which are headed by the main channel number to originate one or a plurality of contents, which channels are given in a hierarchy. The configuration of the sub-channels changes with a broadcasting time band, one of which is exemplified in FIG. 5 which shows a configuration of the sub-channels in a time band (8:00 PM to 12:00 PM) that has a main channel “4”.
In FIG. 5, in broadcasting, sub-channels of Nos. 0 to 4 are selected for 8:00 to 9:00 PM, sub-channels of Nos. 0 and 1 are selected for 9:00 to 10:00 PM, sub-channels of Nos. 0 to 4 are selected for 10:00 to 11:00 PM, and sub-channels of Nos. 0 to 3 are selected for 11:00 to 12:00 PM. Among these, the sub-channel of No. 0 (physical channel No. of 4-0) involves analog broadcasting according to the NTSC (National Television Systems Committee) Standard, while the sub-channels of Nos. 1 to 4 (virtual channels Nos. 4-1 through 4-4) involve digital broadcasting. Also, a TV program broadcast through the channel 4-0 is a prior art analog-broadcast one, an SD (Standard Definition) program broadcast through the channels 4-1 through 4-4 are digital broadcast standard-picture-quality one, and an HD (High Definition) program broadcast through the channel 4-1 is a digital broadcast high-picture-quality one.
There is such a prior art digital/analog broadcasting receiver's channel selection device that decodes and analyzes a broadcasting signal to obtain a VCT (Virtual Channel Table) containing virtual channel information based on PSIP (Program System Information protocol) and hold a channel map storing this table, so that when the user changes or select a channel, based on this channel map, an EPG (Electric Program Guide) functioning as an interface is used to display a channel selection display to thereby operate the key (e.g., UP key/DOWN key) at the body's operation panel or remote-control panel, thus enabling him to change or select the channel.
As described above, a digital/analog broadcast, especially a sub-channel broadcast comparatively soon fluctuates in actual situation owing to temporary suspension in transmission, for example. Therefore, even when channel information is stored as a channel map beforehand for selection of a channel based thereon, the channel selection may fail to display a, broadcast program on the display resultantly. Also, a deficiency of a signal in PSIP (Program System Information Protocol) may cause a failure in channel selection.